Evergreen, often sarmentose shrubs, treelets, or trees with spherical oil
cells in all parts of the plants. Leaves decussate or in whorls of 3-6, simple,
exstipulate, those of a pair occasionally unequal in size, with stellate,
lepidote, or simple hairs, the margin variously serrate, dentate, or entire.
Inflorescences axillary or cauliflorous, cymose, sometimes fasciculate. Flowers
typically radial, strictly unisexual, plants dioecious or more rarely monoecious,
floral cup (receptacle) well developed (the perigon perigynous), subglobose
or cup-shaped, tepals 4-6 (rarely 7), usually minute or fused to a rim encircling
the floral cup, rarely one tepal much longer than the others (in the African
Glossocalyx) or tepals forming a calyptra, the flower centre more or less
covered by a membrane (called floral roof or velum) except for a central
pore through which stamens or styles may emerge; stamens (1-) 2-70, dispersed
irregularly in the floral cup, filaments lacking appendages, anthers with
2 closely adjacent apical pollen sacs opening by a single flap (valve) or
very rarely by two flaps; carpels free but the styles sometimes postgenitally
fused, 3-30, sessile and completely immersed in the floral cup, ovules solitary,
basally attached and anatropous, unitegmic, crassinucellate. Fruit consisting
of the fleshy receptacle which at maturity splits irregularly to expose (1-)
3-25 small drupelets with a conspicuous red or orange aril (in the neotropical
species), the endocarp stony.

The Siparunaceae comprise 2 genera, the neotropical Siparuna with at least
70 species from Mexico and the West Indies to Paraguay and Argentina and
the West African Glossocalyx, with one species, G. longicuspis Benth., in
Cameroon, Gabon, and the island of Fernando Pó. The family is sometimes
included in the Monimiaceae but is more closely related to other lauralean
lineages, especially the Gomortegaceae and Atherospermataceae, than it is
to the Monimiaceae sensu stricto, a group of 22 poorly circumscribed genera,
including Monimia, Tambourissa, Hedycarya, Peumus, and - in Ecuador - Mollinedia.
Siparuna is readily distinguished from Mollinedia by having pollen sacs opening
by valves (vs. longicidally), drupelets enclosed in the fleshy floral cup
until maturity (vs. drupes exposed throughout their maturation), a conspicuous
orange or red aril atop each drupelet (vs. drupes lacking an aril), and several
embryological features, such as basally attached ovules (vs. pendant ovules)
and integuments with one integument (vs. ovules with two integuments).

Dioecious or monoecious sarmentose shrubs, treelets, or trees to 40 m high,
aromatic due to abundant quantities of volatile oil in oil cells throughout
the plant, sparsely or densely pubescent, the hairs stellate, stellate-lepidote,
lepidote, or simple, older leaves sometimes glabrous. Leaves decussate or
in whorls of 3, 4, or 6, petiolate, the margin dentate, serrate, or entire.
Cymes unisexual or bisexual, axillary and/or on leafless nodes. Flowers radial,
strictly unisexual, pedicellate, the floral cup subglobose or cup-shaped,
rarely urceolate or flask-shaped, completely enclosing the stamens or carpels
except for a variably-sized pore in the centre through which the styles or
stamens may protrude, the 4-6(-7) tepals minute, triangular, rounded, or
spatulate, or forming a rim encircling the floral cup or a calyptra (S.
decipiens), the flower centre covered by a slightly or strongly raised and
variously differentiated floral roof (velum); stamens usually 5-9, occasionally
1 or up to 70, free, rarely concrescent, dispersed irregularly in the floral
cup, with 2 closely adjacent apical pollen sacs opening by a single flap,
rarely opening by two flaps, filaments short, stout, and flattened; carpels
3-30, free but the styles sometimes postgenitally fused, the stigmas papillose
and decurrent. Mature floral cups fleshy and 1.5-3.5 cm in diam. (when dry),
globose, smooth, spiny, or with short tubercles, rarely almond-shaped or
with longitudinal ribs, often crowned by the persistent tepals, when fresh
and mature reddish or rarely yellow and with a strong pungent scent, splitting
irregularly from the apex and spreading to reveal 3-25 drupelets; the drupelets
fresh bluish-grey and with an apical and/or lateral orange or red aril (Pls.
1, 3); the testa black and verrucose.

A genus of at least 70 species, distributed from Central America and the
West Indies throughout northern South America to Paraguay and Argentina;
36 species are currently known from Ecuador, including two species awaiting
description when complete material becomes awailable (Siparuna sp. A and
B at the end of the present treatment). Sterile material of Siparuna can
rarely be identified with certainty. Nine [10 are keyed out as monoecious
in the key] of the Ecuadorean species are monoecious, and this breeding system
in Ecuador is highly correlated with entire leaf margins.